A mass spectrometer
can provide a quick and accurateidentification
of a substance from a verysmall sample.

How does a Mass
Spectrometer Work?

The instrument works by vapourising
the sample (turning it into gas).
The sample passes through an electron beam which knocks
offsome electrons
from the molecules
and turns them into ions.
The chargedions are accelerated
towards a detector.
A strongmagnetic
field makes the ions follow a curvedpath
instead of moving in a straight line.Ions with a small
amount of mass curve
the most
and ions with a large
amount of mass curve the least.

A recorder draws a graph
called a mass spectrograph
(usually just called a mass spectrum)
which shows a peak for
each ion detected.
The position of the peaks
show the mass to chargeratio
and this is used to identify the
substances which are present in the sample.